Cement and Energy

I • • • The slots are located in a wear-protected area of the pockets. During operation the aeration slot openings remain constant, cooling air is thus evenl y d istributed and air quantity remains constant throughout the operating period . The cooling air leaves only through the s lots and pockets. The losses between adjacent plates and grate rows is eliminated. Due to the di rect aeration system the cooling air is always Jed directly into the clin ker bed. The specific air load of the grate is reduced by 50% in the ki ln discharge area. Courtesy: World Cement, Nov. I996 • • Longer p late service life due to the increased self– cooling ofthe plate, as well as reduced resulting thermal load and wear due to clinker wearing on clinker in the kiln discharge area. The grate plate service life has been excellent, they have now been in operation for over three years. T he s uccess of this system , however, wil l be determi ne d no t o nl y by i ts recuperative per fo rma nce, but also by its mechanical reliability. REDUCING PRESSURE LOSS AND SAVING ENERGY WITH A VORTEX FINDER VANE SYSTEM T he most important d imensional factors in centr ifugal separators are throughput volume, pressure loss and degree of fraction separation. Of these, pressure loss increasingly constitutes the most sig nificant economic e leme nt, both in existing p lants and new ly des ig ned centrifugal separators. In particular, the dip tube and the intake form have a decisive e ffect on flow behavio ur. The measure of greatest impo rtance is the use of low pressure-loss di p tube designs in the intake zone, whe re pressure loss is by far the largest. The reason for the economic significance of this measure is primari ly because during the service l if e of the separator, arou nd 90% of total costs derive from the energy required to compensate for pressure losses. Flow guidance in the inrake zone must ensure tha t a h ig h degree of uniformity is achieved between the intake and rotationa l flows in t he separation chamber. Unde r practical cond itio ns, deviatio ns o f up to 200% f rom o ptimum leve ls are to be found and t hese have a n extremely negative effect o n energy consumption and separation behaviou r. Using approximation, scientists have calc u lated t he phys ica l connectio ns between pressure l oss, volume flow and separation behaviour for the purposes of ideal models. For pract ical operation, the re are suffi c ient criteria ava ilable fo r an up- to-date assessment of the economic performance of centrifugal separators. Thus, on the basis of the best intake design, it is possible to concentrate ru lly on the mai n cause of exhaust pipe pressure losses. Initial Situation Earl ier studies suggested a reduction in the overall pressure losses through the recovery of part of the velocity energy by means of a diffuse dip tube. There is a conside rabl e d ifference between theoretica l and actual fl ow behaviour in the separator. 9